The certificate holder of a vehicle permanently removed from service must notify the Director of such action in writing within forty-eight (48) hours, indicating whether the owner "junks" the vehicle, sells it or transfers title to it, no longer uses it for hire, or whether the tags have been stolen, or the registration of the vehicle has been revoked by the Maryland Motor Vehicle Administration. When the vehicle is so out of service, all registration cards and other papers issued by the Director to the owner shall be returned by the owner with notice that the vehicle is out of service. The certificate holder shall paint out all identifying marks and numbers indicating that the vehicle was used as a taxicab. The Director shall hold the certificate until its normal expiration date, or until the holder applies for transfer of the certificate to another vehicle prior to such date and within a period of ninety (90) days. If a vehicle is not placed in service under the certificate within ninety (90) days, the certificate may be revoked. The certificate holder shall notify the Director when any taxicab covered by a certificate is temporarily taken out of service for a period longer than five (5) days, explaining why the vehicle is out of service.